The mosque attack happened during dawn prayerson Sunday, although news only emerged onMonday, as communications have been disruptedby the state of emergency.

It took place in the town of Konduga, 35km (22miles) from the Borno state capital, Maiduguri,where Boko Haram was established in 2002,launching its first attack seven years later.

Twelve further civilians were killed at Ngom village,closer to Maiduguri, reports say.

Boko Haram has not commented on the mosqueattack but news of it came as a video emerged ofthe group's leader, Abubakar Shekau, saying hisfollowers had carried out recent attacks includingsome that targeted the police and the military.

He said this showed that the army's claims to haveinflicted heavy losses on the group were "lies".

It is not clear why the mosque was targeted - oneexplanation is that members of a local vigilantegroup may have been praying there.

Several such groups have been set up since theemergency was declared in Borno and twoneighbouring states in May.

Boko Haram frequently attacks churches but it hasalso occasionally targeted mosques and preachersdisagree with their views.

The attackers wore military uniforms, officials say,which they may have taken during recent attacks ona barracks.

Following a lull immediately after the emergencywas declared, there has been a recent spate ofattacks, blamed on Boko Haram, which have leftsome 160 people dead.

But Mr Moro said these were the "desperate antics"of a group trying to show it was still relevant.Thousands of extra soldiers have been sent to theregion since the state of emergency wasannounced.

The military cut mobile phone networks when theyimposed the state of emergency, saying theywanted to make it more difficult for the militants toorganise attacks.

However, some local officials have said this preventscivilians from getting help.